[opendtv] Re: 20060807 Mark's Monday Memo

  • From: "Manfredi, Albert E" <albert.e.manfredi@xxxxxxxxxx>
  • To: <opendtv@xxxxxxxxxxxxx>
  • Date: Fri, 11 Aug 2006 18:42:46 -0400

Donald Koeleman wrote:

> It's all 16:9, but whether this is anamorphic (just as
> with many regular analog 16:9 broadcasts, PAL Plus is
> dead, btw and has been for years), or all full horizontal
> resolution, I can not say for sure. If there are any
> broadcasts using non square pixels, then it will be the
> 1080i ones, as per Tom's BBC examples. 720P seems to be
> always 1280*720.

In the BBC example, I can see that non-square pixels seem acceptable, at least 
in the trials they've been having.

I think what Tom is saying is that if the 1080 is transmitted as interlace, 
then you don't need the full 1980 horizontal pixel res. Because the effective 
vertical res will be, say, 0.7 * 1080 = 756. With a 16:9 aspect ratio, the 
horizontal resolution can be limited to 1344, and you will have effectively 
"square pixels."

True, Tom, although you actually do benefit from increased horizontal 
resolution, even if the vertical isn't as high. So an interlaced image with 
1980 horizontal pixels should still look better than the 1344 image, given the 
right conditions.

On the French HDTV example:

> Bert, gathering from your list, I think you were put of
> by the list of minimum requirements a screen must posess
> to receive the HD ready logo, this doesn't say anything
> about the actual broadcasts.

It does. Here's the excerpt:

http://www.tf1.fr/lachaine/programmes/emissions/0,,3307180,00.html

"La Haute Définition (HD), c'est une image en 16/9, de 1080 lignes de 1920 
pixels, plus de 2 000 000, c'est-a-dire 5 fois plus riche en détails."

The above, at the top of that page, is their somewhat oversimplified definition 
of the HD image. Then they get into what HD ready receivers must support:

"Qu'est ce qu'un ecran 'HD ready'?

"Un ecran 'HD ready' est un ecran permettant d'afficher une image 16:9eme d'au 
moins 720 lignes (soit une resolution native minimale de 1280x720) ***et 
acceptant en entree les formats video 1280x720p50, 1280x720p60, 1920x1080i50 et 
1920x1080i60***. Les resolutions des ecrans 'HD ready' en vente dans le 
commerce sont en general: 1280x720 ou 1366x768 ou encore 1920x1080 (dits 'full 
HD')."

So they say that a "proper" HDTV screen must be at least 1280 X 720 and 16:9, 
and they list the popular TV screen options for HD ready sets as including 1366 
X 768 and 1920 X 1080.

But the part I highlighted states that the formats an HD ready set must be 
capable of receiving "at the input" are 1280 x 720 at 50 or 60p, and 1920 X 
1080 at 50 or 60i.

So at least at TF1, there's no shred of doubt left. HD means square pixels and 
16:9 aspect ratio.

Bert
 
 
----------------------------------------------------------------------
You can UNSUBSCRIBE from the OpenDTV list in two ways:

- Using the UNSUBSCRIBE command in your user configuration settings at 
FreeLists.org 

- By sending a message to: opendtv-request@xxxxxxxxxxxxx with the word 
unsubscribe in the subject line.

Other related posts: